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| Titel |
Ice nucleating particles over the Eastern Mediterranean measured at ground
and by unmanned aircraft systems |
| VerfasserIn |
Daniel Weber, Jann Schrod, Jaqueline Drücke, Christos Keleshis, Michael Pikridas, Martin Ebert, Bojan Cvetkovic, Slobodan Nickovic, Holger Baars, Eleni Marinou, Mihalis Vrekoussis, Jean Sciare, Nikos Mihalopoulos, Joachim Curtius, Heinz G. Bingemer |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250146582
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| Publikation (Nr.) |
 EGU/EGU2017-10611.pdf |
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| Zusammenfassung |
| During the intensive INUIT-BACCHUS-ACTRIS field campaign focusing on aerosols,
clouds and ice nucleation in the Eastern Mediterranean in April 2016, we have measured the
abundance of ice nucleating particles (INP) in the lower troposphere both with
unmanned aircraft systems (UAS) as well as from the ground. Aerosol samples were
collected by miniaturized electrostatic precipitators onboard the UAS and were
analyzed immediately after collection on site in the ice nucleus counter FRIDGE
for INP active at -20˚ C to -30˚ C in the deposition/condensation mode (INPD).
Immersion freezing INP (INPI) were sampled on membrane filters and were analysed in
aqueous extracts by the drop freezing method on the cold stage of FRIDGE. Ground
samples were collected at the Cyprus Atmospheric Observatory (CAO) in Agia
Marina Xyliatou (Latitude; 35˚ 2’ 8” N; Longitude: 33˚ 3’ 26” E; Altitude: 532 m
a.s.l.).
During the one-month campaign, we encountered a series of Saharan dust plumes that
traveled at several kilometers altitude. Here we present INP data from 42 individual flights,
together with OPC aerosol number concentrations, backscatter and depolarization retrievals
from the Polly-XT Raman Lidar, dust concentrations derived by the dust transport model
DREAM (Dust Regional Atmospheric Model), and results from scanning electron
microscopy. The effect of the dust plumes is reflected by the coincidence of INP with the
particulate mass (PM), the Lidar retrievals and the predicted dust mass of the model. This
suggests that mineral dust or a constituent related to dust was a major contributor to the ice
nucleating properties of the aerosol. Peak concentrations of above 100 INP std.l−1 were
measured at -30˚ C. The INPD concentration in elevated plumes was on average a factor of
10 higher than at ground level. The INPI concentration at ground also agreed with PM levels
and exceeded the ground-based INPD concentration by more than one order of
magnitude. Since desert dust is transported for long distances over wide areas of the
globe predominantly at several km altitude, we conclude that INP measurements at
ground level may be of limited significance for the situation at the level of cloud
formation.
This project received funding from the European Union’s Seventh Framework
Programme (FP7) project BACCHUS under grant agreement no. 603445, and the European
Union’s Horizon 2020 research and innovation programme ACTRIS-2 under grant agreement
No 654109, and the Deutsche Forschungsgemeinschaft (DFG) under the Research Unit FOR
1525 (INUIT). |
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